Abstract: Under alternating temperature stratification ( high temperature 13 - 15℃ 12 h everyday and low temperature 0 - 4℃ 12 h everyday) condition, the effect of GA₃ on the change of partial signal molecule was studied during the process of breaking dormancy in Aralia elata seed. The resultswere as following: 200 mg/L GA3 of acetone solution significantly p romoted germination rate of Aralia elata seed, decreased the content of the ABA, and increased the content of the endogenous GA₃ and CaM, meanwhile, improved activity of the NADKase and PM Ca^{2 +} -ATPase evidently. It can be concluded that signal molecule participated in and regulated the course of the breaking dormancy in A ralia elata seed.

Key words: Aralia elata, Seed dormancy, GA₃, Alternating temperature stratification, Signal molecule